1. The present invention relates to an apparatus for operating an alarm switch incorporated in a compact circuit breaker.
2. Description of the Related Art
Some circuit breakers such as wiring breakers incorporate an alarm switch for sending an alarm signal to a distant place when the circuit breaker performs a tripping operation due to a failure such as short-circuit. In such an alarm switch, a microswitch is used as the switch body and is generally housed in either the left or right pole of the circuit breaker.
In such a conventional circuit breaker configuration, in order to actuate the alarm switch so that it operates when the circuit breaker performs a tripping operation, typically, an alarm switch actuator is provided so as to abut directly on a latch of a central pole portion which is one of the constituent members of a switching mechanism and wherein the alarm switch actuator rotates in response to a spring force of a switching spring. In the alternative, the alarm switch actuator is arranged so as to abut an operating rod connected to the latch so as to project sidewards (for example, see Japanese Utility Model Post-exam. Publication No. 58-24362).
However, the foregoing conventional configurations have the following disadvantages.
In the configuration wherein the alarm switch actuator is arranged so as to abut directly on the latch, it is impossible, in view of the small size of the latch, to provide two alarm switch actuators to abut on the latch at the same time. Therefore, an alarm switch can only be provided on either the left or the right circuit breaker pole and not both.
On the other hand, in the configuration wherein the alarm switch actuator is arranged so as to abut an operating rod which is coupled to the latch, it is possible to provide two alarm switches on one side of the latch if the two alarm switches are aligned side by side in the axial direction with respect to the operating rod. Alternatively, it is possible to provide two alarm switches, one on the left circuit breaker pole and the other on the right circuit breaker pole, if the operating rod is arranged such that it projects left and right. However, in this configuration, the operating rod must extend through a partition between the right and left poles in the body casing so that it can rotate as the latch rotates. Accordingly, a large window must be opened in the partition between the right and left poles thereby making the insulation between the two alarm switches and the conductor at the central pole portion of the circuit breaker difficult to configure. Particularly in the case where two alarm switches are provided on one side of the latch, the insulation of the alarm switch near the central pole also becomes difficult to configure.